The present, invention relates to a formfitting connection with break-away function in one direction between two components, for example for use with a movable barrier arm for controlling the passage of motor vehicles. In particular, the invention relates to a formfitting connection between a barrier arm of a vehicle barrier arranged along a defined length in a receptacle of a barrier head disk. When assembled, the barrier head disk may be connected directly, or rotationally through a gearbox, to a rotatable shaft on the barrier head of a harrier column of the vehicle barrier, along an axis perpendicular to the pivot axis of the barrier arm, and in the direction facing away from the barrier head disk.
It is known in the art to formfittingly connect the barrier arm of a vehicle barrier to a barrier head disk which, in turn, is connected directly or is rotationally fixed to a barrier arm shaft of a vehicle barrier. For this purpose the barrier arm is arranged in a longitudinal receptacle of the barrier head disk that establishes a formfitting, rotationally fixed connection between the barrier head dish and the barrier arm in the pivot direction of the barrier arm.
Friction-locked connection elements with a break-away function are typically used in order to implement the connection of the barrier arm disk to the barrier arm in a direction parallel to the pivot axis of the barrier arm. Preferably the friction-locked connection elements are designed as break-away screws, which break off upon application of a force component perpendicular to the pivot direction of the barrier arm when the force component exceeds a specified value, thus enabling the barrier arm to drop with the aim of avoiding damage to the barrier arm and to the vehicle.
However this arrangement has the disadvantage that the break-away screws must be screwed in, or tightened, as much as possible during assembly of the vehicle barrier such that the break-away screws are already heavily prestressed in the assembled state of the vehicle barrier. This entails risk that the formfitting connection in the direction perpendicular to the pivot axis of the barrier arm may loosen from an applied low force in a direction facing away from the barrier head disk, which leads to interference with the operation of the vehicle barrier. In the reverse case, when the screws are insufficiently tightened, mounting of the arm is not robust. In the end, the required moments for breaking the screws are within too wide a tolerance range so there is a risk that, the break-away function becomes unreliable.